Toothed piece for a geared motor, series of geared motors and connection

ABSTRACT

In a toothed piece for a geared motor, series of geared motors and connection, the toothed piece, for a connection with a motor shaft of the electric motor, having at least a first toothing in a first axial region, and having at least a second toothing in a second axial region, the second toothing meshing with a running toothing of a further toothed piece of the gear unit.

FIELD OF THE INVENTION

The present invention relates to a toothed piece for a geared motor, aseries of geared motors and a connection.

BACKGROUND INFORMATION

U.S. Pat. No. 3,242,998 describes a toothed piece, driven by a toothedmotor shaft, for a connection to an output shaft, which has a firsttoothing in a first region and a second toothing in a second region. Inthis case, an internal toothing must be produced in a complicated andexpensive manner.

A shank pinion is also described as a toothed piece in EuropeanPublished Patent Application No. 0 989 316. However, during mounting,centering may only be provided in a costly manner.

In German Patent Published Patent Application No. 26 07 363, the toothedpiece has two helical toothings. However, centering during mounting isagain costly.

German Published Patent Application No. 296 03 748 describes a pin foran adapter, the pin being usable for centering upon insertion.

Geared motors are conventional whose motor shaft drives anexternally-toothed pinion, whose toothing meshes with anexternally-toothed gear wheel having a running toothing or running gear.

To reduce noise, involute toothings having a non-vanishing helix angleare used for these toothings. A disadvantage in this case is that,during the transmission of torque, axial forces develop which must beabsorbed by further components such as bearings.

Therefore, it is an object of the present invention to provide a pinionfor a geared motor in such a manner that less expensive parts may beused in the gear unit or, in a more cost-effective manner, parts mayeven be omitted in the gear unit.

SUMMARY

According to an example embodiment of the present invention, theforegoing and other beneficial objects may be achieved by providing atoothed piece for a geared motor according to the features describedherein, and by providing a connection according to the featuresdescribed herein.

Features of the present invention with respect to the toothed pieceinclude that, for a connection to a motor shaft of the electric motor,the toothed piece has at least a first toothing in a first axial region,and at least a second toothing in a second axial region, the secondtoothing meshing with a running toothing of a further toothed piece ofthe gear unit. In this context, it may be provided that the secondtoothing may be implemented with a different pitch circle diameter thanthe first toothing. Therefore, on the motor side, different toothedpieces are useable within one size for different variants. The toothedpieces are able to be implemented with always the same first toothing onthe motor side, and with different second toothings on the gear unitside. In this manner, a motor shaft of the same kind may be used withinthe size for each variant, it being possible to realize differenttransmission ratios at the first input stage of the gear unit. Anotheraspect is that a high torque may be able to be transmitted from themotor shaft to the toothed piece with the aid of the first toothing.

In an example embodiment of the present invention, the motor shaft has adriver toothing which meshes with the first toothing of the toothedpiece. Not only is a high torque transmittable, but the toothings mayalso be produced inexpensively using industrially common toothingmachines.

In an example embodiment of the present invention, the first and secondtoothings are each helical toothed and have the same algebraic sign forthe helix angle and/or have the same helix angle. This may provide thatthe components of axial force, generated by the helical toothings, ontothe toothed piece itself may be influenced in the design by theselection of the helix angles and the toothing data so that a reduced,resulting component of axial force onto the toothed piece itself isattainable. Improvements in the design of the gear unit may be achievedby this reduction in the resulting axial force onto the toothed pieceitself. Other parts may be implemented more cost-effectively or evendispensed with, such as suitable retaining rings, etc.

In an example embodiment of the present invention, the first and secondtoothings are involute toothings. Such industrially common toothings maybe produced inexpensively, easily and quickly on suitable productionmachinery.

In an example embodiment of the present invention, the first and/orsecond toothing is/are external toothings. The toothed piece has mayhave a compact form and therefore may be produced inexpensively.External toothings may be manufactured simply, quickly and inexpensivelyusing large milling cutters, and after the hardening, using largegrinding wheels.

In an example embodiment of the present invention, the pitch circlediameter of the first toothing is larger than the pitch circle diameterof the second toothing. A smaller gear wheel may also be used in thefirst gear stage, including second toothing of the shank pinion and gearwheel, which means it may also be possible to realize small transmissionratios.

In an example embodiment of the present invention, the toothed piecehas, at its motor-side end, a pin or plug which is inserted in such amanner into a corresponding cut-out in the motor shaft that, uponinsertion into the cut-out, it may be used for centering the toothedpiece. This may provide easy and quick production. In particular, thecentering may also permit a highly precise, and at the same time,quickly executable assembly.

In an example embodiment of the present invention, the pin may becylindrical. The pin may be produced inexpensively.

In an example embodiment of the present invention, the pin may beconical. This may provide that assembly may be accomplished particularlyquickly, and even if the toothed piece deviates from the ideal positionprior to or during assembly, a centering may take place automaticallycorrectly upon insertion into the motor shaft.

In an example embodiment of the present invention, the pin may have aknurling. The knurling may have a greater hardness than the material ofthe motor shaft, and therefore may be able to be pressed into the motorshaft, accompanied by material deformation. Therefore, in the case ofsmall torques, the connection of the toothed piece to the motor shaft isimplemented via this press connection. Only after a critical torque isexceeded is the driver toothing of the motor shaft usable with the firsttoothing of the toothed piece for the torque transmission.

In an example embodiment of the present invention, the toothed piece mayhave a cut-out which, upon introduction into the motor shaft, is useablefor centering the toothed piece. The toothed piece may have only a shortlength, and therefore may need less storage space and assembly space. Inparticular, it may be rotatable on a smaller space volume during theassembly. It also may have less volume of material. Because of thehigher torque to be transmitted and the greater hardness for the machinegrinding of the toothings, the material of the toothed piece may be moreexpensive than the material for the motor shaft, for which structuralsteel may also be used.

In an example embodiment of the present invention, the first and secondtoothings may be included by a single toothing. This may provide thatproduction may be particularly simple, and a high transmission ratio maybe realized.

In an example embodiment of the present invention, the driver toothingof the motor shaft may be an inner toothing. This may provide that itmay be produced inexpensively using industrially common productionmethods, e.g., by striking, broaching, original forming and/or milling,etc.

Features of the present invention with respect to the series of gearedmotors are that the series includes at least one size, and each sizeincludes one or more variants of geared motors. Within one size,substantially identical motor shafts, which in each case are connectibleand/or connected to a toothed piece, are usable for different variants.Within one size, at least one variant includes a toothed piece whosefirst and second toothings are different. At least one further variantincludes a toothed piece whose first and second toothings are identical.In this context, it may be provided that, by the use of differenttoothed pieces, it may be possible to realize a wide range of differenttransmission ratios. In particular, not only the toothing data may bevaried, accompanied by an essentially constant pitch circle diameter,but also the pitch circle diameters may be varied within one size forthe variants. This may enlarge the range of transmission ratiosconsiderably.

In addition, it is possible to use an involute toothing as a firsttoothing, and as a second toothing, to use a pinion for a helical-bevelgear stage, or a pinion for another type of gear stage such as, forexample, a planetary gear stage, a gear stage having a spiroidallytoothed wheel or other bevel gear stages. Therefore, even a motor shaftwhich is always substantially identical may be used for various types ofthe input gear stage.

Features of the present invention with respect to the connection from afirst rotating part via a toothed piece to a part having a runningtoothing are that the toothed piece has a second toothing which mesheswith the running toothing. The toothed piece has a first toothing whichmeshes with a driver toothing of the first rotating part. The helixangles of the first and the second toothing are selected so that thedirection of the axial force, generated by the driver toothing and firsttoothing, onto the toothed piece itself, and the direction of the axialforce, generated by the running toothing and second toothing, onto thetoothed piece itself are opposite, in order to decrease the resultingaxial force onto the toothed piece itself. This may provide that thecomponents of axial force, generated by the helical toothings, onto thetoothed piece itself may be influenced in the design by the selection ofthe helix angles and the toothing data so that a reduced, resultingcomponent of axial force onto the toothed piece itself is attainable.Improvements in the arrangement of the total device may be achieved bythis reduction in the resulting axial force onto the toothed pieceitself. Other parts may be implemented more cost-effectively or evendispensed with, such as suitable retaining rings, etc.

Further example embodiments and developments are set forth below.

The present invention shall now be explained in detail with reference tothe accompanying Figures.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic view of an example embodiment of a toothed pieceaccording to the present invention.

FIG. 2 is a schematic view of an example embodiment of a toothed pieceaccording to the present invention.

FIG. 3 is a schematic partial cross-sectional view of a motor adapted tomesh with the toothing of the toothed piece.

FIG. 4 is a partial cross-sectional view illustrating an exampleembodiment of the present invention.

FIG. 5 is a schematic view of an example embodiment of a toothed pieceaccording to the present invention.

FIG. 6 is a schematic view of an example embodiment of a toothed pieceaccording to the present invention.

FIG. 7 is a schematic view of an example embodiment of a toothed pieceaccording to the present invention.

FIG. 8 is a schematic view of an example embodiment of a toothed pieceaccording to the present invention.

DETAILED DESCRIPTION

FIG. 1 shows a shank pinion 3 which has a first toothing 1 and a secondtoothing 2, first toothing 1 having a smaller pitch circle diameter thansecond toothing 2. First toothing 1 and second toothing 2 each have anegative helix angle of the same amount. In other exemplary embodimentsof the present invention, different amounts may also be used.

FIG. 2 shows a shank pinion 23 which has a first toothing 21 and asecond toothing 22, first toothing 21 again having a smaller pitchcircle diameter than second toothing 22. First toothing 21 and secondtoothing 22 each have a positive helix angle of the same amount.

The helix angle is denoted symbolically in FIGS. 1 and 2 by threeparallel marks. In the figures, M designates the motor-side axial end ofthe shank pinion, and G designates the axial end of the shank pinion onthe gear unit side.

In FIG. 3, a motor 31 is partially indicated, whose motor shaft 32 has abore hole having a driver toothing 34, implemented as an inner toothing,with which first toothing 1, 21 of shank pinion 3, 23 meshes.

In addition, the motor shaft has a cut-out 33 for centering a shankpinion provided with a corresponding pin. In other exemplary embodimentsof the present invention, motor shaft 32 may be implemented without acut-out, shank pinions 3, 23 according to FIG. 1 or 2 then being used.

FIG. 4 shows a shank pinion 42 which has a cylindrical pin 43 forcentering upon insertion into motor shaft 41. With second toothing 2 asrunning toothing, shank pinion 42 meshes with gear wheel 44 of the gearunit.

Driver toothing 45, arranged as a helical toothing and meshing withfirst toothing 46 arranged as a helical toothing, generates a componentof axial force onto the toothed piece. The running toothing of gearwheel 44, together with the second toothing of shank pinion 42,generates an oppositely directed component of axial force onto thetoothed piece itself. Therefore, the resulting component of axial forceonto the toothed piece itself has only a small or even vanishing value,depending upon the selection of the helix angles and the toothing data.

FIG. 5 shows a shank pinion 51 having a conical pin 52 for the centeringin a correspondingly conical cut-out and/or bore hole in the motorshaft.

FIG. 6 shows a shank pinion 61 which has a first toothing 63 and asecond toothing 64. In addition, shank pinion 61 has a cut-out 62 forthe centering, the motor shaft having a corresponding form or, in otherexemplary embodiments of the present invention, the motor shaft beingprovided with corresponding parts.

FIG. 7 shows a shank pinion 71 having a pin provided with a knurling 72.Since shank pinion 71 is made of a hardened material and/or a materialhaving a greater hardness, shank pinion 71 is able to be pressed intothe softer motor shaft, made of structural steel, accompanied bymaterial deformation.

Instead of structural steel, other materials may also be used which areless hard than the shank pinion.

FIG. 8 shows an example embodiment of the present invention, shankpinion 81 having a helical-toothed toothing 82 which, on the motor side,meshes with the correspondingly helical-toothed driver toothing of thecut-out of the motor shaft, and on the gear unit side, meshes with therunning toothing of a correspondingly helical-toothed gear wheel of thegear unit. Therefore, it may only be necessary to produce a singletoothing, which may be particularly simple and cost-effective.

Thus, shank pinions according to FIG. 8, for which toothing data suchas, e.g., root diameter, outside diameter and pitch circle diameter ofthe first and of the second toothing are identical, may be used in aseries of gear units having several gear ratios within one size. Inaddition, shank pinions according to FIG. 1 are usable with the samemotor shaft. Since, therefore, different shank pinions having, in eachcase, a different second toothing but identical first toothing may beused, it is possible to realize a wide range of transmission ratios.

In further example embodiments of the present invention, the foregoingmay also be used for other types of toothing. For example, the firsttoothing of the shank pinion is a helical-toothed involute toothing, andthe second toothing meshes with a bevel gear or a spiroidally toothedwheel. Thus, cylindrical or non-cylindrical second toothings are alsopossible.

In other example embodiments of the present invention, the foregoing maybe used not only for gear units, but also for other devices whichinclude a connection from a first rotating part, such as a shaft, via atoothed piece to a part having a running toothing. In this context, inthe manner shown in the Figures, the toothed piece may be arranged witha first and second toothing, each having the same algebraic sign of thehelix angle, such that the axial force components generated in eachinstance act in the opposite direction. Therefore, the aspects andeffects indicated above may also be achieved for other devices.

1. A toothed piece of a geared motor, including an electric motor and agear unit, comprising: a first toothing arranged in a first axial regionadapted for connection to a motor shaft of the electric motor; a secondtoothing arranged in a second axial region adapted to mesh with arunning toothing of a further toothed piece of the gear unit; and a pinarranged at a motor-side end of the toothed piece, the pin configured tobe inserted into a corresponding cut-out of the motor shaft to centerthe toothed piece; wherein the motor shaft includes a bore hole with aninterior having a driver toothing, the first toothing meshing with thedriver toothing.
 2. The toothed piece according to claim 1, wherein thefirst axial region is arranged on a motor side and the second axialregion is arranged on a gear unit side.
 3. The toothed piece accordingto claim 2, wherein the first axial region is arranged at a motor-sideend of the toothed piece.
 4. The toothed piece according to claim 2,wherein the second axial region is arranged at an end of the toothedpiece on the gear unit side.
 5. The toothed piece according to claim 2,wherein the toothed piece is configured as a shank pinion.
 6. Thetoothed piece according to claim 2, wherein each of the first toothingand the second toothing include helical toothings having at least one ofa same algebraic sign for a helix angle and a same helix angle.
 7. Thetoothed piece according to claim 2, wherein the first toothing and thesecond toothing include involute toothings.
 8. The toothed pieceaccording to claim 2, wherein at least one of the first toothing and thesecond toothing includes an external toothing.
 9. The toothed pieceaccording to claim 2, wherein a pitch circle diameter of the firsttoothing is smaller than a pitch circle diameter of the second toothing.10. The toothed piece according to claim 1, wherein the pin iscylindrical.
 11. A connection from a first rotating part to a piecehaving a running toothing, comprising: a toothed piece including asecond toothing meshed with the running toothing and a first toothingmeshed with a driving toothing of the first rotating part, the firstrotating part having a bore hole, the driving toothing internal to thebore hole, the first toothing meshing with the driving toothing, thetoothed piece including a pin inserted into a corresponding cut-out ofthe first rotating part to center the toothed piece; wherein helixangles of the first toothing and the second toothing are arranged sothat a direction of a helix force generated by the driver toothing andthe first toothing and a direction of an axial force generated by therunning toothing and the second toothing are opposite to reduce theresulting axial force.